N-2-hydroxyethyllactamide

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

10 Aug -06 Sep 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2016

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

version April 2004

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Department of Health -The Department of Health of the Government of the United Kingdom

Test material

Test material information

Constituent 1

Reference substance name:

N-2-hydroxyethyllactamide

EC Number:

226-546-1

EC Name:

N-2-hydroxyethyllactamide

Cas Number:

5422-34-4

Molecular formula:

C5H11NO3

IUPAC Name:

N-2-hydroxyethyllactamide

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations: control and 100 mg/L, from the bulk test preparation at 0 hours and from the pooled replicates at 48 hours
- Sampling method and storage: All samples were taken and stored frozen prior to analysis.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A nominal amount of test item (100 mg) was dissolved in test water and the volume adjusted to 1 liter to give the 100 mg/L test concentration. The prepared concentration was inverted several times to ensure adequate mixing and homogeneity.
- Controls: yes

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Source: in-house laboratory cultures
- Age of parental stock (mean and range, SD): 1st instar Daphnia magna
- Feeding during test: no
- Food type: mixture of algal suspension (Desmodesmus subspicatus) and Tetramin® flake food suspension
- Frequency: daily (for culture)
- Medium: Elendt M7 medium

METHOD FOR PREPARATION AND COLLECTION OF EARLY INSTARS OR OTHER LIFE STAGES: The test was carried out using 1st instar Daphnia magna. Gravid adults were isolated the day before test initiation, such that the young daphnids produced overnight were less than 24 hours old. These young were removed from the cultures and used for testing.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test conditions

Hardness:

250 mg/L as CaCO3

Test temperature:

test start and test end: 22 °C

pH:

test start: 7.5 - 7.6
test end: 7.9

Dissolved oxygen:

test start: 8.6 - 8.7 mg O2/L
test end: 7.5 mg O2/L

Nominal and measured concentrations:

nominal: control and 100 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel
- Material, size, headspace, fill volume: 150 mL glass beakers (covered)
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Reconstituted water (ISO medium)
- Culture medium different from test medium: yes: Elendt M7 medium for the stock culture and Iso medium for the test
- Intervals of water quality measurement: Water temperature was recorded daily throughout the test. Dissolved oxygen concentrations and pH were recorded at the start and termination of the test

OTHER TEST CONDITIONS
- Adjustment of pH: Elendt M7 Medium: 7.9 ± 0.3; Reconstituted Water – ISO Medium: 7.8 ± 0.2
- Photoperiod: 16 hours light and 8 hours darkness with 20 minute dawn and dusk transition periods
- Light intensity:between 200 and 1200 Lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Immobilization or adverse reactions were recorded at 24 and 48 hours after the start of exposure. The criterion of effect used was that daphnia were considered to be immobilized if they were unable to swim within 15 seconds after gentle agitation.

VEHICLE CONTROL PERFORMED: no

RANGE-FINDING STUDY
- Test concentrations: 0.10, 1.0, 10 and 100 mg/L.
- Results used to determine the conditions for the definitive study: the test concentrations of the definitive test were based on the results of the range -finding test

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 2

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Behavioural abnormalities: A sub-lethal effect of exposure was observed in the 100 mg/L test concentration. One Daphnia was trapped at the surface.
- Mortality of control: no
- Others: Biological results of the range-finding test, the analytical results of the definitive test and the analytical results are summarized in the tables 1-3 in section "Any other information on results incl. tables".

Results with reference substance (positive control):

potassium dichromate
EC50 (48h): 0.64 mg/L

Reported statistics and error estimates:

An estimate of the EC50 values was given by inspection of the immobilization data.

Any other information on results incl. tables

Table 1: Results of the range-finding test

Nominal Concentration (mg/L)	Observations (Initial Population: 10 Per Replicate)
	24 Hours		48 Hours
	Cumulative Immobilized Daphnia	Observations	Cumulative Immobilized Daphnia	Observations
Control	0	10 N	0	10 N
0.10	0	10 N	0	10 N
1.0	0	10 N	0	10 N
10	0	1 T 9 N	0	1 T 9 N
100	0	1 T 9 N	0	10 N

 N = No sub-lethal effects observed

T = Trapped at surface

Validity criteria:

The test was considered as valid since:

No more than 10% of the control daphnids show immobilization or other signs of disease or stress.

The dissolved oxygen concentration at the end of the test is equal to or greater than 3 mg/L in the control and test vessels.

Table 2: Results of the definitive test after 24 h

Nominal Concentration (mg/L)	24 Hours
	Cumulative Immobilized Daphnia (Initial Population: 5 Per Replicate)						Observations
	R1	R2	R3	R4	Total	%	R1	R2	R3	R4
Control	0	0	0	0	0	0	5 N	5 N	5 N	5 N
100	0	0	0	1*	1	5	5 N	1 T 4 N	5 N	4 N

R1 – R4 = Replicates 1 to 4

N = No sub-lethal effects observed

T = Trapping at the surface

*Single immobilized daphnid considered to be due to natural causes given that less than 10% immobilization was observed.

Table 2: Results of the definitive test after 48 h

Nominal Concentration (mg/L)	24 Hours
	Cumulative Immobilized Daphnia (Initial Population: 5 Per Replicate)						Observations
	R1	R2	R3	R4	Total	%	R1	R2	R3	R4
Control	0	0	0	0	0	0	5 N	5 N	5 N	5 N
100	0	0	0	1*	1	5	5 N	1 T 4 N	5 N	4 N

R1 – R4 = Replicates 1 to 4

N = No sub-lethal effects observed

T = Trapping at the surface

*Single immobilized daphnid considered to be due to natural causes given that less than 10% immobilization was observed.

Table 3: Analytical results

Time Point	Nominal Concentration of Test Item in Test Sample	Sample Preparation Factor	Determined Concentration of Test Item in Test Sample	Percentage of Nominal Concentration
	cnom	F	c
[hours]	[mg/L]		[mg/L]	[%]
0	Control	1	<LOQ	-
	100	100	115	115
48	Control	1	<LOQ	-
	100	100	114	114

LOQ = Limit of Quantification

- = not applicable

Applicant's summary and conclusion

Validity criteria fulfilled:

yes